The Joint Collaborative Team on Video Coding (jct-vc) of itu-t wp3/16 and iso/iec jtc 1/ sc 29/ wg 11 held its tenth meeting during 11-20 July 2012 at the City Conference Centre (ccc), a k. a

JCTVC-J0315 AHG5: Context reduction for MVD coding [C. Kim, J. Kim, J.H. Park (Samsung)]

In the current HM, the first two bins of motion vector difference (MVD) are coded with context. The remaining bits are coded with bypass mode. The two flags, abs_mvd_greater0_flag, and abs_mvd_greater1_flag, are used for context at both flags. From the statistical analysis, the distribution between ‘0’ and ‘1’ is similar, so, the use of context is not much benefit for separating ‘0’ and ‘1’. Therefore, we perform abs_mvd_greater1_flag rather than abs_mvd_greater0_flag where abs_mvd_greater0_flag is coded with bypass mode. The proposed method reduces context from 2 to 1. No loss and complexity is observed both normal QP and lowQP (1,5,9,13). Moreover, total bins (context ₊ bypass) is reduced by 0.1% and contexts is also reduced 1.5% average for RA and LD

The proposal changes the sequence of syntax elements (and deviates logically from what is done elsewhere e.g. in transform coding) and introduces a new binarization (cannot be interpreted as truncated unary anymore)

Several experts express opinion that benefit is not clear.

No support by other companies

No action.

JCTVC-J0385 Cross-check of Context Reduction for MVD Coding in JCTVC-J0315 [W.-S. Kim (TI)] [late]